Mevion Medical Systems files plan for IPO


Mevion Medical Systems has filed plans for an initial public offering to raise $69 million to expand its lower-cost proton therapy technology for use in radiation treatments for cancer patients.

The Littleton-based company says its technology offers a safer alternative to conventional X-ray radiation therapy, which is also less expensive than conventional proton therapy.

Formerly known as Still River Systems, the firm has raised $135 million in funding since its founding in 2004, making it one of the best-funded health care startups in MassachusettsTop shareholders in Mevion include ProQuest Investments (14 percent of shares), Venrock (8.4 percent of shares), and CHL Medical Partners (6.4 percent of shares).

The firm generated $7.6 million in revenue for the nine months that ended June 30 this year, all of it from the company’s first installation of a proton therapy system at Barnes-Jewish Hospital in St. Louis, Mo. Mevion says it has a backlog of signed purchase contracts for its systems, which have a total value of $257.6 million.

Kyle Alspach has worked in journalism in Massachusetts since 2005 and was one of the original staff writers at BetaBoston.
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